1. Field of the Invention
The invention relates to a method of treating stored coal to allay dusting during storage or handling and reducing moisture penetration of coal stored in the open atmosphere.
2. Prior Art
The exposed surface of stored coal, especially coal stored in the open atmosphere is subject to oxidation and weathering which can cause the physical disintegration and dusting especially during subsequent handling and transportation. This is particularly harmful to metallurgical coal which rapidly loses its swelling and other specific characteristics after a relatively brief open air storage period. Such coal will then have to be used as steam coal at a much lower value. The use of water on stockpiled coal to prevent dusting is objectionable in that weathering is accelerated, coal pile effluent increased, and the coal freezes in cold weather to such an extent as to render it difficult to handle.
Methods disclosed in the prior art for allaying the dusting of coal have generally involved the use of oils or aqueous mixtures of deliquescent chemicals such as calcium chloride, magnesium chloride and potassium carbonate. The low freezing point and hygroscopic action of the chemicals is said to keep the coal moist and thereby prevent dusting or freezing in the coldest weather. The use of chlorides can present corrosion problems to equipment with which the coal is contacted.